@Nyn - this functionality was not intended to be used with your "read", "to-read", "currently-reading" shelves. It was intended purely for "genre" type shelves, which surely you are not moving books around on weekly? Do you not just pick a genre shelf to put a book on and leave it there?

The to-read etc shelves you should just use the "Sync" functionality to handle your updates. That gives you all the power to do stuff like removing a tag, adding a tag, setting a custom column value etc.